Oil circuit breaker



y 3, 1934- H. TRENCHAM ET AL 1,965,440

OIL CIRCUIT BREAKER Filed April 13, 1952 I I)lIIIIIIIIIII'IIIIIIIIDIIIlllllllllllllll'lllll EIIIIIIIIIII 1/ I "1111 n "11, "111, 1 "11," k I!lhventcrs: Hen ry Trench am,

Herbert; C. Heath,

Their Attorney.

Patented July 3, 1934 OIL CIRCUIT BREAKER Henry Trencham, Ruislip, andHerbert Christopher Heath, Wembley, England, assignors to grenfiralElectric Company, a corporation of New Application April 13, 1932,Serial No. 605,098 In Great Britain April 13, 1931 7 Claims. (Cl.200150) suitable metal. The cap 6 is adapted to enclose one end of theinsulating tube '7 forming an explosion chamber which is thus capable ofswinging about the contact 2.

For the purpose of directing the oil blast in accordance with thecircuit opening movement, the tube 7 is connected to the operating linkor lift rod 8, as at '7', and forms part of the movable element of thecircuit breaker. Within this tube is pivotally mounted at '7' the bridgeor contact bar 9 arranged longitudinally of the tube, one end beingadapted to engage the contact finger 10 which is in electrical contactwith the fixed contact 2 and which extends through cap 6 within thetube, and the other end adjacent or projecting from the open. end of thetube and adapted to engage the other stationary contact 1.

The pivotally mounted contact bar is resiliently biased, for example bymeans of a flat spring 11, so that it is, in the open position of thecircuit breaker, out of engagement with the contact finger 10. The endof the pivotally mounted contact bar projecting from the open end of thetube is thus maintained in such a position that when the tube 7 is swungclockwise by the operating link of the circuit breaker from the opencircuit position (as shown in dotted lines), the end of the contact bar9 is first brought into engagement with the stationary contact 1 and oncontinued movement of the operating link is swung round about its pivotand brought into engagement with the finger 10 within the tube.

On opening movement of the common actuating means including theoperating link the spring bias on the contact bar maintains theprojecting end thereof in engagement with the contact finger l. Theother end of the conductor is separated under the action of the springbias so that contact at the inner end of the tube is initially broken,forming an arc which produces within the tube a pressure driving the oilwithin it towards the oil blast contacts. On further movement of theinsulating tube, these latter contacts separate and the oil blastextinguishes the are between them. The oil blast, therefore, is directedcontinuously into and through the are at the outer open end of theinsulating tube during the entire switch opening movement.

The arrangement wherein the insulating tube, which forms an explosionchamber, is moved bodily by the switch actuating means permits acomparatively small explosion chamber structure and a short pressuregenerating are for a given opening stroke of the switch.

It should be understood that our invention is The present inventionrelates to oil circuit breakers of the type wherein a blast of oil isproduced between separable contacts so that rapid extinction of the arcformed therebetween is effected.

In circuit breakers of the oil blast type the operation has beenproposed wherein pressure is produced in the oil in which the contactsare immersed by the arc formed between separable contacts, and thispressure is utilized to drive a blast of oil across other separablecontacts in series with the first-named, or pressure-producing contacts,so that the arc formed between the second, or oil-blast pair of contactsis rapidly suppressed.

The object of the present invention is toprovide an improved oil circuitbreaker of the above type which is eflicient in operation, of simpleconstruction, and is made up of a relatively small number of parts.

In carrying the invention into effect, the explosion chamber in whichthe pressure is generated for effecting the oil blast is moved inaccordance with the circuit opening operation. To this end theconducting crossbar or bridging member of the circuit breaker carryingthe movable contact adapted to bridge the stationary contacts ispreferably enclosed within an insulating casing and movable with respectthereto, the insulating casing being arranged to be moved by meansconnected to the actuating mechanism of the circuit breaker. Thecrossbar itself is so biased within the casing that it tends to bemaintained out of engagement with one of the stationary contacts, thatconact and the co-operating contact surface on the crossbar constitutingthe pressure-generating contacts. By this means it is ensured thatseparation at the pressure-generating contacts takes place before theseparation of the oil blast contacts.

Our invention will be more fully set forth in the following descriptionreferring to the accompanying drawing, and the features of novelty whichcharacterize our invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

The single figure of the drawing is an elevational View, partly insection, of a circuit breaker constructed in accordance with the presentinvention.

In the drawing, 1 and 2 indicate two stationary contacts supported bybushing insulators 3 extending through the cover 4 of a tank 5containing an insulating liquid 5' as oil in which the contacts areimmersed. Pivotally mounted on contact 2, as at 2, is a conducting capmember 6 of not limited to specific details of construction andarrangements thereof herein illustrated, and that changes andmodifications may occur to one skilled in the art without departing fromthe spirit of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States, is:

l. A circuit breaker of the oil-blast type comprising relatively movablecontact structure immersed in an insulating liquid, said contactstructure arranged to form a pressure generating arc and another are inseries therewith upon opening of the circuit, a casing forming anexplosion chamber in which said pressure generating arc is formed fordirecting a blast of insulating liquid from said chamber through theother arc, and means operatively connected to said contact structure andexplosion chamber casing for moving the same so that the blast directedfrom said chamber is moved through said are in a continually changingdirection in accordance with the circuit opening operation.

2. A circuit breaker of the oil-blast type comprising an insulatingliquid, relatively movable contact structure immersed in said liquidforming a pressure generating arc and another are in series upon openingof the circuit, an insulating casing forming an explosion chamber withinwhich said pressure generating arc is formed, and means for efiectingangular movement of said insulating casing in accordance with thecircuit opening operation for directing through an angle a blast ofinsulating liquid from said chamber across the other arc.

3. A circuit breaker of the oil-blast type comprising an insulatingliquid, relatively movable contact structure immersed in said liquid, aninsulating casing pivotally mounted forming an explosion chamber openonly at one end thereof, said contact structure arranged to form an arewi hin said explosion chamber and another are transversely of andadjacent the opening of said chamber upon opening the circuit, actuatingmeans for opening said contact structure and moving said explosionchamber about its pivotal mounting arranged so that pressure generatedby the are within said chamber directs a blast of insulating liquid fromthe open end of said chamber through said other are throughout themovement of said explosion chamber, and means limiting the movement ofsaid explosion chamber so that the pressure generating arc is short ascompared with said other arc.

4. A circuit breaker of the oil-blast type com prising an insulatingliquid, contact structure including a pair of stationary contacts and abridging member immersed in said liquid, an insulat ing casing formingan explosion chamber pivotal- 1y connected with respect to one of saidstationary contacts and enclosing said bridging member so that apressure generating arc is formed in said chamber upon opening of thecircuit, and actuating means for rotating said insulating casingdirecting a blast of insulating liquid through another arc during thecircuit opening operation.

5. A circuit breaker of the oil-blast type comprising contact structureincluding a pair of stationary contacts and a. bridging member immersedin an insulating liquid, an insulating casing forming an explosionchamber open at one end pivotally connected at its other end withrespect to one of said stationary contacts, said bridging member beingdisposed within said casing and resiliently biased into engagement withone of said stationary contacts, and an operating rod pivotallyconnected to said bridging member and to said insulating casing arrangedso that an initial pressure generating arc is formed within said chamberfor directing a blast of insulating liquid through the other areadjacent the open end of said chamber concurrent with pivotal movementof said casing.

6. A circuit breaker of the oil-blast type comprising an insulatingliquid, coacting contact structure including a pair of stationarycontacts and a movable bridging member forming two breaks in seriesimmersed in said liquid, an insulating casing enclosing one of saidstationary contacts and a part of said bridging member, said casingbeing closed at one end thereof, and contact actuating means arranged sothat a pressure generating arc is formed between said bridging memberand a fixed contact within said casing adjacent the closed end thereofand another are is formed between the other fixed contact and bridgingmember exteriorly of said casing and transversely of the open endthereof, the pressure generated within said casing by said firstnamedare causing a blast of insulating liquid from said casing through saidsecond-named arc.

'7. A circuit breaker of the oil-blast type comprising an insulatingliquid, coacting contact structure including a pair of fixed contactsand a movable bridging member immersed in said liquid, an insulatingcasing forming an explosion chamber open only at one end thereof, one ofsaid fixed contacts being located within said casing at a point remotefrom the open end thereof, the other fixed contact being locatedexteriorly of said casing and adjacent the open end there of, saidcasing enclosing a part of said bridging member, and actuating means forsaid bridging member arranged so that the arc formed between saidbridging member and an enclosed fixed contact causes a blast ofinsulating liquid from said chamber through the arc formed between theother fixed contact and bridging member exteriorly of said casing.

HENRY TRENCHAM.

